anoxia
by solfreyja
Summary: Of all the glorified chores Shigaraki Tomura tries to pass off to Katsuki as extra-combat missions, Nomu duty is by far his favourite. It's oddly soothing, checking on each Nomu one by one, and re-mixing the chemical agent needed to keep them stable and alive. Of course, Todoroki Shouto would show up to ruin the one peaceful activity he could say he enjoyed. (Villain AU, TDBK, FWB)
1. Chapter 1

Of all the glorified chores Shigaraki Tomura tried to pass off as non-combat tasks Katsuki has had to do, Nomu duty is by far his favourite.

He's also one of the few who are both competent enough trust not to fuck it up (because the price for fucking the Nomus up is very, very great), and the only one with an actual preference for it, so he had more or less ended up as their main handler. It was oddly soothing, checking on each Nomu one by one, and re-mixing the chemical agent needed to keep them stable and alive.

Occasionally he would be joined by one of his more competent coworkers, either working in silence while they talked at him and communicating with occasional grunts and nods or making idle chatter while he worked, depending on who it was and his mood for the day.

Most of them though, avoided going in there at all, looking distinctly nauseous whenever they had to crack the heavy iron door open to speak to Katsuki (because while Katsuki does have a phone, there are very few people he can be trusted to take a call from) take over a shift because the handful of people who weren't deathly afraid of them were out doing more interesting assingments for the night.

(And of course, there were some coworkers who were not allowed within 20 feet of the Nomu room, no matter the occasion, with all the delicately whirring machinery and dangerous chimera-creatures it housed. Katsuki had the pleasure of being allowed to punish them however he felt appropriate for the infraction, which meant that there had never been a single infraction while he was on duty.)

He understands why they trigger uncanny valley fight or flight reactions in people, he really does, and to be completely honest he can't even blame them for it (although of course, he will scoff at their trepidation in all given opportunities, because he's still Bakugou Katsuki). He glances over the pinkish-bloody exposed gray matter floating in the vat of clear chemical in front of him, sitting disgustingly atop pairs of too-large eyes – maybe eyeballs would be more accurate – and rows of shiny white teeth, not nearly enough space between them, held together in a vaguely humanoid shape by pallid leather skin that looked unnaturally tight around its own flesh.

In all honesty, Katsuki's almost fond of the fucking things. Dabi had, on one memorable occasion, lewdly hinted-suggested that he should crawl in the tank and fuck one of them if he liked them so much. Smiling, Katsuki had kindly offered to rearrange his features to look like one instead.

Not that it would have been a huge change on him, the freak.

He's jolted out of his thoughts by the unmistakeable sound of the industrial heavy duty doors dragging open, a low, reverbating metallic screech that echoes in his peaceful lab.

"Let me guess," he drawls, not turning around. There's really only two people it could be at this hour, the only others who worked in the lab regularly. "Dabi's out today, so it's gotta be _fucking_ Deku. What the fuck do you want, shitty nerd?"

"Ah, not exactly," says an amused voice behind him. Katsuki pauses between putting the pH meter in the next tank.

"Todo-"

A beat.

"Shouto?" His voice comes out softer, against his will.

"Mhm," Shouto hums, stepping close enough behind him that he can feel his cool breath ghost over his ear, causing the hair on the back of his neck to stick up as if he'd been electrocuted. He's doing it on purpose. Katsuki's fingers twitch, he wants to strangle him.

"You are _not_ fucking me in the Nomu room," Katsuki says with as much venom as he can muster, straightening and turning to face him properly. Shouto tilts his head, causing wisps of white hair to fall over his face, catching in his long lashes. He looks only mildly interested, blinking at him curiously.

"Is that all I'm good for?"

"Clearly," Katsuki sneers, already irked by his perfect composure and face and the distraction it brings. He's not used to being alone with him outside of field jobs (which mostly tended to devolve into something sexual by the end anyway), and he definitely doesn't need him around tonight, with everyone either sleeping or out, in the most secluded wing of the warehouse where it's almost certainly just the two of them, when he has _fucking work to do goddamnit._ "What do you _want._ "

Shouto takes a step back, and Katsuki almost takes a step _forward_ without thinking about it, catching himself with his foot in the air.

"Shigaraki sent me," he admits, averting his gaze to glance around at the rows of pulsating creature-things encased in vats. "He told me to... tell you to teach me. About the Nomus. Taking care of them."

It made no fucking sense. He and Deku and Dabi already covered the shifts between themselves perfectly. And Shouto was an idiot. A very good-looking idiot, that Katsuki worked well with, on _field missions._ Not in a lab that was already partly breaking down, to add _distraction_ to Katsuki's list of safety hazards and bad protocol that he already had to deal with.

"Why," Katsuki says, choosing his words carefully, "the fuck."

"Apparently," says Shouto, "he wants to double the stock. Three handlers working separately aren't going to be enough." He's still facing away from him, but his eyes flicker back periodically, probably hoping Katsuki wouldn't notice. He does notice.

Fucking _hell_. If Shigaraki had actually sent him, with a purpose, Katsuki couldn't chase him out.

"We'll be working in pair rotations, when the new batch comes in, but I think you're the one who spends most time in here currently, so..." Shouto trails off. _So what_ , Katsuki wants to say, _I have to be your goddamn babysitter?_

" _'_ _We'_ ," he instead quotes flatly, fishing out the pH meter from the greenish-tinged liquid. He's left it in too long, rendering the reading completely useless. Shouto watches him reset it and put it back in quietly. Katsuki wishes he would look away again.

They wait for it to go off again in silence, listening to the soft bubbling of the tanks and the occasional Nomu gurgle.

"This _is_ happening, no matter how you feel about it, Katsuki," Shouto says finally, breaking the thick air between them. He _knows that._

"That's Ground Zero to you," Katsuki mutters under his breath, irritated. Shouto never used anyone's codenames when referring to them, and he didn't have one himself.

He takes out the device out when it beeps again, noting down the value, then stands bent over the the vat for longer than necessary, watching the Nomu's exposed brain mass quiver wetly. A single bubble floats to the surface and pops, a tiny droplet of the solution splashing onto his skin, stinging slightly.

Whatever. _Whatever_.

"Bring me the hydrogen phosphate," he grunts, not meeting his eye. "It's in the third cabinet, on the left, first row. If you slept through your high school science class, tell me now, so I can kill you and make this easier for both of us."

Shouto offers him an expression that might pass as a smile if Katsuki were being generous (he wasn't), then saunters over to the cabinets obediently (for once in his fucking life) to bring him his phosphate. Katsuki watches the line of his back as he sifts through the racks. He sighs.

"And for the love of god, put a fucking lab coat on."

Whether during their field missions or meetings or simply when their paths had crossed in the medium sized warehouse they currently called base, "methodical" and "precise" were not words Shouto would have applied to Bakugou Katsuki, but they were what came to mind now, watching him carefully calculate exact ratios of chemicals to mix, still-irritated grimace highlighted by the green glow of the vat behind him. Shouto is caught between thinking he looks out of place or that he must have been born to stand around scowling as he looks over a clipboard in a shady bio-engineering lab.

He supposes there's no real contradiction with Katsuki's established character though, having never considered him _not_ methodical or precise. Despite all the chaotic energy he carried, Katsuki was never more than a switch away from distilling all of himself and his rage and his power into a laser pointed precision strike of a person concentrate, focused single-mindedly, absolutely onto his task. All of his actions, his seemingly erratic attack patterns and outbursts had the underlying current of an extremely sharp and _methodical_ mind behind them. Whether he was making split second decisions and running on purely adrenaline and violence or quietly double checking his formula at 2 in the morning didn't matter.

It doesn't surprise him, exactly, but it does leave him feeling rather distinctly out of his element, being around this calmer side of him. He supposes there's a first for everything.

Or a second, or a third. It's been at least a week since he's started coming down here, every night except Wednesdays and Thursdays (which is when Touya has the lab and Touya... does not want Shouto around if at all possible), sometimes finding Izuku but usually Katsuki, working away. Izuku is patient and always slows down everything he's doing to let Shouto have a chance to take it in.

Katsuki, of course, shoots on ahead as he does, barking commands and short explanations at Shouto as he goes along. Shouto is fairly sharp, he knows this, and he doesn't need things spelled out to him to catch on, but Katsuki had been doing this for 3 years before Shouto had even stepped foot in the lab, and he was no born bio-chemist.

He also, really needs to find a better sleep schedule to accomodate his now-daily shifts.

He can't complain too much, at any rate, becase Katsuki does look rather nice in his lab coat (lightly stained with who knows what), leaning over the vat to reach the heavy machine behind it, pen clamped between his teeth and clipboard between his arm as he adjusts the temperature with a few short clicks on the ancient looking monitor mounted on the side of it.

Shouto likes how the sharp point of his canines just out just slightly over the rest of the even rows of teeth around the pen, the pearly enamel glinting dangerously in the dim light of the lab. It makes him want to reach out and feel them for himself, draw the pad of his thumb over the pointed edges until they make his hands bleed, or until Katsuki rolls his eyes and pushes him off or demands he do something else.

He's been staring, he realises, but if Katsuki has noticed he doesn't say anything. Katsuki should say something, it's weirding him out, but he continues to squint at his work, the steady stream of explanation and commands from earlier faded out as his concentration shifts.

"You're oddly professional in here," Shouto comments, knowing it's the wrong thing to say. Katsuki's head immediately snaps up to him, glowering. Ah, there he is.

"The fuck is that supposed to mean?" he demands, lips pulling back into a snarl, baring more of those teeth that Shouto likes so much. He shrugs.

"Quieter. More focused. More agreeable. Not throwing things around. It's weird," he informs him, and is rewarded for his honesty with the metal point of a clipboard smacking him in the face.

"I'm always professional," Katsuki growls. "Who the fuck do you think I am?" He raises the clipboard again, apparently satisfied by the yelp of surprise it had earned him, and Shouto grabs his arm mid-swing, shooting him a reproachful look. He doesn't tell him that he enjoys his company equally either way, tempting as it is to see the reaction it would draw, because Katsuki doesn't need to know that.

"Is this the last one?" he asks instead, changing the subject. Katsuki gives him a nasty glare (but no more nasty than usual), yanking his arm and clipboard back from his grip.

"No," he says, stalking over to the large cylindrical tank in the back of the room that Shouto had for some reason assumed wasn't part of Katsuki's job. The light from it is blue, instead of the filthy algaea-green of the smaller tanks, and the nomu inside it is at least twice the size of the other ones, and shiny black instead of white. There's a narrow set of aluminum stairs leading up the side to an deck at the top that would definitely not pass safety regulations in any legitimite laboratory. Katsuki knocks against the glass a couple times as he passes by it toward the ladder, almost like a greeting. Shouto eyes the Nomu warily for signs of a response, unsure about its level of consciousness and sentience. He really wishes he could be home in his small apartment right now sleeping instead.

Katsuki's taken a single step on the ladder – but just the one, paused and staring at the clipboard in his hand as if he's noticed something wrong. He steps off, checking both of his hands and his shirt, then turns back to look at Shouto, eyes scanning his entire body in a fraction of a moment. He scoffs.

"What are you, made of glass?" he says, looking inconvenienced. Shouto raises an eyebrow, coming to a halt several feet behind him next to the tank. "I didn't even hit you that hard."

"What?" he says. Katsuki stares at him carefully, scrunitizing his entire face. He blinks back, completely nonplussed.

"You're bleeding," he says slowly, almost accusingly. Shouto runs his hand over his face, feeling a warm wetness around his right cheekbone. His fingers come away bright red. Huh. From the clipboard?

"So I am," he mutters, turning to squint at his reflection in the glass tank. Katsuki has an odd expression on his face, he can see out of the corner of his eye, quietly watching him as he pokes carefully at the bloody gash under his eye.

It's a lot deeper than he thought, almost a half centimeter into his face – he didn't even think he had much flesh to cut through there, but the shock of blood gushing out from under his eye says otherwise. How sharp was the point of that thing? He's even got some blood on his coat, bright red droplets dying the absorbent cloth.

"You don't feel it?" Katsuki says, considering him as he inspects the wound with eyebrows stitched together.

Shouto shakes his head, pressing a cold hand on it and pinching the edges together to try and still the bloodflow. He could probably cauterize it, but it's really not deep enough to be worth it – not like he doesn't already have enough burn scars on his face as it is. "It's a third degree burn, most of the nerves are gone. Do you have any bandages? I don't really want to drip into the tanks."

Katsuki crosses his arms and leans against the large tank with his shoulder, looking pensive.

"No. Just stay away from them until it dries." A short pause - hesitation? That's new. "Is that from your old man, then? Quirk accident?"

He grins at him wryly. "My mother."

Katsuki's eyebrows raise. Shouto turns to him swiftly, stepping away from the tank. "Are you really interested? I'll tell you if you want."

For a moment it's silence, just the hum of the machines and the creatures around them, Katsuki drops his gaze and kicks at the floor. He reaches over with one hand to punch the sequence in for tank drainage in the numkey, shoving it in his coat pockets afterwards when the confirmation beep sounds, still not meeting Shouto's eye, glaring at the floor as if the dirty tiles had offended him personally, as if they were the source of all of his problems somehow.

"Tell me then," he says at last, managing to sound petulant even through his low growl. He hates it so much when Shouto doesn't just give him what he wants immediately. It's one of Shouto's only sources of entertainment in recent times, riling up the infamously short-fused villain over inconsequental bullshit like this.

He hums, not responding immediately, taking a moment to study the looming black Nomu sort-of floating (starting to crumple down slowly, as the liquid level goes down) in the glorified aquarium over Katsuki's shoulder instead as he muses on how to apprach the topic, ignoring Katsuki's rapidly deepening scowl of impatience.

It's not as ugly as the smaller ones in the other tanks, which isn't a very big compliment. They're all varying shapes of haphazardly sewn together flesh lumps (now that he thinks of it, he wonders if hs brother's had any hand in putting the newer ones together, with All for One and his natural abilities no longer with them), but at least this one has the advantage of not having to look like a bloated corpse with its slick and shiny smooth-ish finish instead of the ashen paper-thin excuse for skin the other ones sported. There are a few rips here and there, especially around its torso where the leather can't quite stretch enough to accomodate the bulging muscles underneath it.

It looms behind Katsuki (who's switched from glaring at the innocent tile patterns to glaring at Shouto) almost threatheningly, like a twisted impression of a bodyguard, giving Shouto the absurd feeling that he might sic it on him if he annoys him too much.

Though really, he notes drily as he takes in the murderous expression on his face (over absolutely nothing, too – he's ridiculously entertaining like this), Katsuki would probably much rather tear him apart with his own hands than get the creature to do his dirty work. He has no doubt he fantasizes about it on a fairly regular basis.

"You've heard of quirk marriages, right?" he says at last, when it looks like Katsuki might be about to burst a vein. He gets a terse nod as reply – of course he's heard of them, probably suspected about Shouto's unusual double quirk being a product of one, always sharper than he let on. "Good. It's something that shouldn't still exist in this day and age, but my father always had a piss-poor excuse for ethics, for someone supposed to be the second greatest hero of all time."

Katsuki's mouth is a thin line. Shouto looks away from it.

"On his own, he never could defeat All Might as the number one hero, so he came up with another plan." The water in the Nomu's tank was drained down to it's stomach. Shouto wishes someone would have thought to put some pants on the thing, not feeling very positively on having to stare at it's unnecessarily anatomically correct crotch while talking about his parents. "With his fame and money, he easily convinced my mother's family to agree to the marriage. All so he could use her, with her complementary quirk, to bear him the perfect heir."

He doesn't have to tell Katsuki that he's standing with him.

"In all the memories I have of her, my mother is always crying," he says, carefully leaving off any emotion from his tone, keeping it a simple stating of facts. "She told me that she couldn't stand to look at my ugly left side, and then dumped boiling water on my face."

The look on Katsuki's face would perhaps be best described as 'unnerved', but it's ony here for a moment and then it's gone, covered up quickly with a scoff and averted eyes.

"Nice sob story," he mutters, pushing himself off from the now empty tank and making his way over to the barrels of active components on the end of the room behind him, shooting a sneer as his way. Shouto is positive he knocks into his shoulder with more force than necessary on purpose. "Don't have any to exchange."

"Didn't ask," Shouto replies curtly, keeping a wary eye on him. Katsuki grunts back non-committally, slight strain showing in his voice as he lifts one of the barrels up over his shoulders. The muscles in his shoulders ripple delightfully with the movement even through the thick white coat he wears, distracting Shouto briefly from the thoughts that inevitably surface whenever he speaks about either of his parents at any lenght.

There's a subtle, but undeniable awkwardness in the air as Katsuki gets to work in filling up the tank with the correct amounts of various liquids, climbing up and down the ladder with each empty barrel, threathening to blow Shouto's face off and shooing him away whenever he got close or tried to help. He grumbles something about organic contaminants at him, although really, he's already stopped bleeding, and he'd had no problem barking orders at him before.

The tiredness he'd been holding at bay for the past couple of hours suddenly washes over Shouto, with nothing to distract him, coming in waves until he can feel himself sway and the edges of his vision feel blurry.

Resigned, Shouto takes his place sitting at the foot of the tank, feeling rather like he's been put into time-out (for what offense, he can't even fathom – simply existing probably counted in Katsuki's book). He pulls his knees up and rests his chin on them, arms crossed around himself. His wristwatch ticks away next to his ear, and he doesn't need to look at it to know it's nearing 3. His eyes close, once, twice, and when they shut a third time, he doesn't bother opening them again.

"Tell me," Katsuki had said, irritated that he's making him ask, asking despite it.

The half-assed bastard always had a way of pulling words out of Katsuki's mouth, not because he's too stupid to need things spelled out to him, but apparently for the simple hell of it, despite knowing full well how much it gets under his skin – or maybe because of it, he thinks, bristling even further at the thought.

It's not that Katsuki gives a shit. He doesn't. Over the years they'd known each other, he's never once felt inclined to dig into the peppermint-coded assholes past, although he'd always had his vague suspicions. He's never allowed himself to reflect too deeply on or question him directly on them, because it's honestly none of his fucking business and he (really) doesn't care about his tragic backstory.

Still, though, it's difficult not to be a little intrigued by him, even for Katsuki. It wasn't every year that the top graduate student of UA's hero course decided to skip the graduation ceremony in favor of murdering his own father in cold blood. The charred remains of Endeavour's headless corpse had been all the news could speak about for the next year and a half, the shock of the number 2 hero's sudden death shaking the entire country to it's core.

Todoroki Shouto had shown up at their base the next day, and tossed Endeavour's severed head at Shigaraki Tomuras's feet, demanding they let him join their shitty club of misfits. It hadn't been a long discussion.

He stands over Shouto now, taking in the sight of him curled up around himself on the _fucking dirty_ floor, sleeping peacefully as if he were laying on the most comfortable bed in the world. Nobody looking at him now could guess the kind of shit he did for a living.

The blood from the freak gash under his eye has rubbed off on the white sleeve of his coat where his cheek rests against it (and he'd had the nerve to insist to Katsuki that it was already dry and he was fine, the brainless moron). Katsuki has to wrestle down the urge to kick him, right in his pretty face.

Instead, he kneels down in front of him and shakes him awake, parhaps too gently. Shouto awakes with a start anyway, looking so on edge that for one bizarre moment Katsuki thinks he's going to punch him, and he's thinking he should have gone with the kick after all, but then he gains his bearings almost immediately, relaxing visibly he realises it's Katsuki standing over him. Which is fucking stupid, because it's a ridiculous notion that Katsuki would be somehow more safe than anyone else in the building.

"Katsuki..." he mumbles, almost whisper level, even though they're alone in the room. His words slur together sleepily, and he blinks and rubs at his eyes at the harsh glow of the flourescent lights. There's a second in which Katsuki has the thought that he should have turned the lights off so they didn't bother him, and then he kicks himself internally for coming up with an idea stupid enough to rival one of Kaminari Denki's. "What... time is it?"

"4 AM," Katsuki replies, in his usual volume. Shouto flinches at the loud voice in his face. He can fucking deal with it. "We're done. Get the fuck up, princess, I'm not locking you in here."

He lets out a soft moan (what the fuck), and pulls Katsuki towards himself by his shirt to hide his face in his shoulder, as if he's a goddamn pillow or something.

"...What the hell," he says intelligently, stiffening at the unfamiliar contact. He's never actually been in very close proximity to a drowsy Todoroki Shouto before, but it apparently had the unfortunate side effect of frying all of his remaining brain cells.

Shouto, either oblivious (unlikely, even in this state) to his discomfort or choosing deliberately to ignore it, stretches one of his (long, elegant) legs across Katsuki's side. He ends up kneeing him under his arm in their awkward position, causing Katsuki to stumble forward between Shouto's legs and have to brace himself on the tank to avoid toppling directly into him and slamming his pretty head into the glass behind him. Katsuki growls, irked, left hanging precariously over him in a strange not-quite embrace.

"I slept maybe 2 hours last night," Shouto mumbles into his neck, as if expecting him to do something about it. "Give me a few minutes."

Katsuki really, _really_ will strangle him one day.

He does deign to raise his head after around 2 minutes and 30 seconds (he counts) blinking blearily up at him and looking as miserable as Katsuki had ever seen him. It'd be funny if he didn't have to deal with it. A few strands of silky white hair stick messily up around his face, and Katsuki absolutely does not think about reaching out and smoothing them back.

"Let's fucking go then, Sleeping Beauty," he deadpans, ignoring the way he continues to stare at him, and making to get up – but he's interrupted by Shouto grabbing him by the hair at the back of his neck with a grip surprisingly solid for the sorry state he's in, and pulling him crashing down clumsily onto his lips, hot and wet and insistent.

Katsuki sputters, torn between the equally instinctive reactions to kiss him back and to knee him in the gut. He does neither, instead freezing in place as Shouto hums pleasantly into his mouth, his long eyelashes brushing against Katsuki's cheek when he tilts his head to fit their lips together better, dragging his velvety tongue across his mouth and tugging at his lower lip with his teeth. The hand in his hair pulls him in deeper, and fuck it, he's worked hard, he sinks into him with a soft groan, one hand coming up to roughly grip his slender jaw, and Shouto melts into him.

It's uncharacteristic, for Shouto to directly initiate anything, to be so pliant and blatantly wanting for his touch, and Katsuki is enamored completely by the soft, wet sounds Shouto gives him so easily instead of his usual tightly controlled breathing. He's almost worried he's inhaled something he shouldn't have while Katsuki wasn't paying attention, but there's nothing in the lab that could produce a high like that.

He's forced to accept that his own presence is simply that intoxicating. He grins lazily, grazing his teeth and biting roughly into the soft flesh of Shouto's lips, and he's made him bleed for the second time that night (Shouto twitches violently but his mouth falls open and his breath hitches high in his throat and the fist in his hair tightens) and he licks it up, savoring the familiar metallic tang like he'd wanted to earlier with the ridiculous red gash he'd created on that perfectly sharp cheekbone.

His free hand twitches at his side, he wants to run it across Shouto's beautifully toned chest and under his shirt but he knows if he does he won't be able to stop and he has to stop, because they're still in the lab and he can't - breathe -

He pulls away sharply, shaking Shouto's grip off, panting, and takes in his now even more disheveled appearance. He's breathing hard, chest heaving, lips puffy and wet with blood and spit. (Katsuki doesn't want to think about how messed up he himself looks.) His eyes look softer than he remembers them, but maybe its the odd blue light from the tank behind him, and Katsuki's shadow falling on his face where he kneels over him.

"What the hell," he says again, as if he hadn't been kissing him back with more fervor.

"I wanted to kiss you,"says Shouto breathlessly, a good deal more awake and in a better mood than he had been. Katsuki licks his lips.

"You're still not fucking me in the Nomu room."

"I'm too tired to fuck you right now. Just the kiss will do," he says, and it sounds like an _apology_. He gives Katsuki's hair a light pet ( _gross_ ) before pushing himself up where he'd slid, back curving as he shifts against the glass. His runs his hand lightly across his own face, touching lightly around the scarred area to locate the newly formed scab on his cheekbone. "How does this look?"

Katsuki doesn't care and doesn't want to think about it, but his mind helpfully flashes back to the story about Shouto's mother pouring water on him, and he can't help but wonder what the aftermath of _that_ had looked like, marveling again at how the objectively ugly scar had done absolutely nothing to diminish the overall beauty of his delicate features. He swallows, hand coming up next to Shouto's own despite himself.

"Better. Hey," he says, ignoring Shouto's wary look. "You said _most_ of the nerves were gone."

"Yes?"

"How much of it can you feel though?" he asks, not bothering to keep the rough edge out of his voice. He runs an experimental finger up the left side of his jaw lightly, carefully scrunitizing his reaction.

"A bit. Katsuki..." he trails off, looking unsure of what to say to him, twisting oddly in his grip.

"Chill the fuck out, I just wanna see," he says, dragging the pad of his thumb across the waxy red tinted skin higher up on his face, pressing harder at the edges where the scar meets smooth skin. He's close enough that their individual breaths ghost over each other, and he can feel Shouto's skin get a bit more chilly in his proximity. "Feel that?"

"Sort of."

He presses higher. "That?"

"No."

He presses his lips there then, smirking to himself at Shouto stiffening – as if he hadn't been all over him moments ago – then nips at the surface of his cheek lightly, pinching the taught skin between his teeth and running his tongue over it.

"Mm?"

Shouto clicks his tongue. "Not really."

He shifts, dragging his lips lightly over his cheek, over the the wound he already knows there's no feeling around, until he reaches where it stretches out across his ear. "How about now?" he says, voice purposefully as breathy as he can make it.

"Yes." Katsuki doesn't miss the small shudder that runs through him. He grins, satisfied, and nips at the ear lightly before pulling back.

Shouto gives him a look that Katsuki doesn't feel like interpreting the meaning of, then stands up abrubtly, almost knocking Katsuki on his ass as he does. He hisses in annoyance, and Shouto tilts his head as he looks down on him, towering.

"I really need to sleep," he offers as explanation, cool and detached. Katsuki aims a kick at his leg, hard, and Shouto winces before dancing out of the way, almost stepping over him, to avoid the next attack aimed at his shin. "Sorry."

The air shifted into something completely different, it's like they had just been discussing weather or a particularly uninteresting piece of news rather than exchanging spit moments ago. Katsuki pushes himself up to his feet with one hand, grinning nastily when Shouto takes several quick steps back towards the door. A much smarter move than letting his guard down enough to _sleep_ in his presence. How laughable.

Shouto stands for a couple more seconds, then gives him a curt nod, turning around swiftly and tossing the white lab coat off onto the rack next to the door. The metal door creaks, and then shuts, and Katsuki is alone again with his beloved lab and the disgusting creatures it houses, just how he likes it.

thanks for reading thus far! this story is meant to be **explicit** in later chaptersand there is a smutty one-shot (and art) in the same verse but of course, i can't very well post it on , so if you're interested in reading the uncensored version please do head on over to Ao3 for it 3

anoxia

in the truly gruesome (one-shot)

drag me into place (art)


	2. Chapter 2

Shouto would like to think he's pretty experienced at avoiding his problems.

He avoided uncomfortable phone calls. He avoided the police. He avoided speaking to his family (even before, when he was on the right side of the law, he hadn't spoken to his mother since she'd given him his scar). He'd avoided using his right side – even though it was a reactive quirk, deeply affected by his emotions - up until the very end of his final year at U.A., when he'd used it to commit patricide.

He is good at it.

It's not that Shouto wants to be alone. (He sticks to Izuku's side like glue.) It's not that he hates him. (He doesn't think he does.) It's not even that he's particularly uncomfortable with opening up to him, about his past, and being vulnerable – he honestly hadn't minded, at all.

In fact, paradoxically, his utter comfort with it _was_ the problem. In no part of the life he had built up for himself (or rather broken down, deliberately and with purpose, into tiny pieces like so many shards of his ice) would there ever be room for attachment or trust.

Shouto kept even Izuku, the person closest to what he would consider a friend now, at arms lenght. Katsuki was not an exception. And neither was Shouto, to him. They both knew this.

Still, he avoids him. He does a good job of it.

He specifically takes on hours he knows he doesn't work, and routes he knows he doesn't walk. (He's not sure when or how he picked up Katsuki's schedule so well, but it's been useful to him in this case and he doesn't want to analyze it further.) He goes on a mission with Toga, of all people.

(Toga spends the entire time either laughing at him for being boring, which he doesn't mind, or speculating on secrets she thinks he has, which is annoying. He wonders if his brother gets the same treatment from her, with how often they seem to be together, and how he, with a violent streak a million times worse than Shouto's, possibly manages to hold off on strangling her.)

He balances his schedule so that his lab shift can coincide with Izuku or even _Touya_ instead of him. It occurs to him that being so diligent in avoiding Katsuki had the unfortunate side effect of making him think about him a lot more than usual.

It's a losing game, he knows it is. Katsuki passes by him in the hallway without so much as a word, only indication he notices him is bumping into his shoulder _hard_ as he walks by him, whatever sort of message he was supposed to get out of that. " _Stop ignoring me_ "? " _Ignore me harder_ "? " _Fuck off and die in a ditch_ "?

(He thinks he might be getting somewhere with that last one.)

"Todoroki-kun."

Izuku. He glances up from his drink (lukewarm water, which had ice in it 5 minutes ago, but drinks never lasted their proper temperature for long around him) as reply. Izuku looks uncomfortable, moreso than usual, hands clasped behind his back and shuffling his feet.

"Todoroki-kun," he says again, punctuating his words with a nervous glance towards the door, "are you and Kacchan... okay?"

Shouto frowns, because drawing attention to himself was the last thing he'd wanted to do. How much does Izuku know? He doesn't think Kacchan – _Katsuki_ , would have said anything to him. What did they even talk bout?

"Why? Is there a reason we shouldn't be?" Izuku grimaces.

"Todoroki-kun, you've turned down every mission with him Tomura's given you since last Tuesday at the very least, and probably for a while before then but that's the first time I know of personally because I had to join Kacchan on that mission as backup and he kept talking about how much better you were as a partner than me and calling you an asshole which is his way of saying he's been thinking about you and Kacchan doesn't think about a lot of people and I think you were with him in the lab that first time but you've always come with me instead after that and I'm flattered but –" Shouto holds up a hand to stop him and pinches his temple between his thumb and forefinger, trying vainly to fight off the tell-tale throb of an incoming migraine.

"I'm not – there's nothing. It's just coincidence." He downs the entire unpleasantly warm glass of water down in one go, then stands up abrubtly. "Aren't there new shipments arriving today?"

Izuku narrows his big, round eyes, clearly not buying it – he's way too perceptive for his own good – but allows him to change the subject.

"They are," he says slowly, "they should have by now actually – I wanted to call you to help set them up."

"Let's go, then," he says, starting briskly down the hallway before the interrogation resumes. Izuku trots after him, mouth clamped suspiciously shut.

They had only just finished carrying the last of the vats and containers in through the rear entry when the metal door that led to the hallway shrieks open, and Katsuki is there. He stops dead in his tracks, then crosses his arms, glare switching between Izuku and Shouto as if he can't decide who deserves his scorn more.

He looks slightly winded, as if he'd run down there from doing something else – which explained his lateness, because Katsuki was never late if he could help it. Bloody murder drips off of every deep breath he takes, and Shouto wants him so bad he aches.

Shouto's fighting a losing game, and he knows it.

Of _course_ Katsuki is too neurotic to leave the setting up of 'his' lab to mere mortals such as Izuku and Shouto. He mentally kicks himself, and he's fairly certain something shows in his expression, because he catches Izuku trying to hide a small smile behind his hand out of the corner of his eye. Katsuki zeroes in on him, and Shouto is almost disappointed.

"Deku... tell Todoroki what to fucking do, I'm not dealing with his shit," he growls, and stalks past them to wrestle his lab coat on.

"We've got it more or less covered, actually," he says before he can catch himself. Katsuki scoffs, pulling his arm through the sleeve and looking more like he was trying to rip a new hole in an opponents body than putting on a piece of clothing. Izuku gives Shouto a look, and Shouto pretends not to see.

They spend the next 45 minutes going through the chemicals from the truck, Izuku quietly whispering to Shouto with instructions where he wasn't sure what to do, and Katsuki fuming as far away from them as possible while still being in the same room.

Whenever he has to ask Shouto for something, or notices some flaw in what he's doing that Izuku doesn't point out (because they're inconsequental flaws, and Izuku is not as big of a perfectionist as Katsuki) he addresses Izuku instead, using him as a messenger between the two. Izuku looks steadily more regretful as it goes on, trying valiantly to catch Shouto's gaze and being carefully avoided.

"Deku, tell Todoroki to stop fucking up my fucking shelves."

"I can hear you, Bakugou."

"Deku, tell him to shut the fuck up."

"Kacchan..."

Really, this is just childish. Shouto had been ignoring him out of nowhere, yes, but they weren't even friends or close in any way besides physical – Shouto knew Katsuki had been under no delusions otherwise. He couldn't be that starved for physical contact.

It reminds him, faintly, of how he had been when they were both still teenagers, and Shouto had refused to use his fire against him in the tournament on their first year. They'd been even less close then, of course, but Katsuki had been the same way then, straddling the line between ignoring him and going out of his way to bump into or otherwise sneer at Shouto whenever they'd been in the same room together.

He'd been baffled at the time, at how personally he'd taken it, but Katsuki was expelled before the end of the year and Shouto was quickly consumed by more important matters than a sulky teenager to give it much more thought.

"Deku, tell Todoroki he's slow as shit and that I'd like to finish this sometime this century so I can stop staring at his ugly mug."

He's honestly way too old for this.

Shouto opens his mouth to retort drily (" _you don't have to keep staring at it_ "), but before he can get anything out, Izuku throws his hands up with a noise of frustration.

They both turn to stare at him.

"I'm fucking _done_ being your messenger pigeon, work it out or have sex or whatever you two do – I'm _out!_ " Izuku says shrilly, cheeks flushed and eyes shining with uncharacteristic anger. Shouto hadn't been aware this was a volume his voice could reach. "Deal with it yourselves!"

He walks right out the door then, and the metal slam echoes deafeningly behind.

Shouto and Katsuki are left in stunned silence. Izuku was shy, polite, _puppy-like_ even. It was rare of Shouto to witness him to showing even visible impatience.

Katsuki is the first to recover. "Useless fuck," he mutters under his breath, kicking over an empty barrel. He then walks over to Shouto, glowering, and forces him out of the way of the shelves he's supposed to be organising.

"Alphabetized, top to bottom, compounds first. Is that too fucking hard for you to grasp, Icyhot, or do I need to teach you English too now?" Katsuki smells so sweet, up close, like the burnt caramel he used to eat scraped of the bottom of the pan as a kid. It's both familiar and overwhelming.

"I can read English just fine. Katsuki."

Katsuki doesn't reply, instead making a low, vaguely threatening sound in his throat as he meticulously rearranges Shouto's handiwork. He puts it back in almost the same positions they were in already. Shouto frowns.

"I'm sorry for avoiding you. It wasn't personal. Just – "

"I don't give a _shit_ ," Katsuki grits out. "Stop talking to me."

"Let me explain myself."

"Fucking stop."

"You were like this in UA too," Shouto snaps, patience running thin. Katsuki turns to him then, knuckles white around the plastic container in his hands, face stony. "I tried talking to you, after the tournament. I was going to apologise. But you – "

 _BANG._

A small explosion – like a firecracker – shoots out of Katsukis's palms, the container bursting apart in his hands. The shelves around them tremble dangerously. From the expression of wide-eyed horror on Katsuki's face, he hadn't meant to do that.

The container was empty. It could have had anything in it. There's only the smell of burnt plastic and smoke, now, both of them frozen in place.

Katsuki's face is ashen and drained of his anger from moments before. He's taken several steps back from the shelf, holding his arms away from himself as if worried they would – well.

"Get the fuck out of my lab, Shouto."

Katsuki's voice trembles as he says it. Shouto closes his eyes for a second, then opens them again to find Katsuki staring at a spot behind him, avoiding his face. He licks his lips.

"I didn't know you had a reactive quirk," Shouto says, making no move to leave.

"I fucking don't," he hisses. "You're a safety hazard. If that container wasn't empty –"

"How is it my fault that you can't control your own – "

"If you would _shut the fuck up and do your fucking job right_ – "

"You're the one acting like a goddamn _child_ – "

Shouto grits his teeth, cutting off his own raised voice. They'd both been shouting. Katsuki snarls and rips his coat off, throwing it on a shelf along with the small bits of plastic blown onto the rows of neatly arranged containers, then stomps past Shouto towards the door. Shouto doesn't turn back.

"Leaving, then?" Shouto calls out coolly, ignoring the strange sinking feeling in his stomach.

"Yep."

"Good."

The door opens, there's a long pause, and then it slams shut, leaving Shouto to clean the mess himself.

But –

The footsteps return. Shouto glances back and barely has time to face and steel himself when Katsuki assaults him, slamming him into the wall with enough force to make the shelf quiver. Shouto blinks at him in alarm, arm up and ready to defend himself necessary, then Katsuki grabs it and pushes him back and then –

And then his mouth is on him, and his hands, everywhere, and Shouto's head drops back against the wall, and he doesn't push him off. His breathing comes out harshes than he likes, but so does Katsuki's and its okay because Katsuki's breath is sweet and warm and – Shouto had been kidding himself, thinking he could avoid him for long, because all it's done is make him want more.

"What -" Katsuki growls, between feverish kisses to his jaw, and neck, and collar, "– the _fuck_ –" he fumbles with his shirt, but it feels like he should be ripping apart his flesh, "– is your _problem_?"

Shouto thinks it's a hilariously hypocritical question, coming from Katsuki, and he wants to laugh, but then Katsuki sucks _sharply_ on the hollow of his neck exactly how he likes it and it comes out a breathy gasp instead. He runs his hands down Katsuki's beautifully-built shoulder muscles, tracing around the curve of his arm and relishing in the skin bared in his sleeveless black shirt.

"I hate your fucking guts," says Katsuki, and Shouto doesn't think that's true but he would probably not have minded, if it were.

Katsuki's given up on his shirt, or simply too impatient to bother, and he's moved on to tugging at his belt instead, glaring as if it was a sentient being that was in his way. Shouto moves to help him but he smacks his hand away (hard enough to sting) and wraps a palm around the metal clasp. Theres a small crack, and the putrid smell of burning metal, and when Katsuki lets go it falls off limply, broken. _That was expensive_ , he should say, but in all honesty he couldn't give less of a shit, not when Katsuki sinks down in front of him, leaning back on his feet and parting his mouth, ready and waiting and eager to -

Katsuki could break everything Shouto owned, if he wanted.

They both stand there, collapsed against each other on the wall, breathing heavily. The room comes back around them, slowly. Shouto doesn't let go of his grip on his hair, and after half heartedly struggling his head away from him for a short while Katsuki gives up and sags back against him, allowing Shouto to hold him up while they both catch their breath. Shouto runs a hand through the sweat soaked blond hair.

"I thought you were going to blow my face off," Shouto says, once he's got his breathing somewhat under control.

"Blew something else."

"Didn't you say we weren't going to have sex in here?"

"Fuck you." Katsuki's voice is muffled against Shouto's shirt, and he sounds very drained, and very hoarse. Shouto glances once again at the pieces of plastic container scattered around them.

"I didn't know you had a reactive quirk," Shouto says again. Katsuki stiffens against him, and doesn't reply, pretending to be very interested in fixing their pants back properly. He messes with the broken belt buckle some, twisting it around as if a different angle would clasp together.

"Mine is too," says Shouto. Katsuki knows, he's seen his control waver with his flared emotions plenty _._ "Obviously. But you – keep better control of it than me. I've never seen you accidentally blow something up before."

Katsuki sighs, frustration apparent in his voice. "I told you, it's fucking not. It's just – in very specific situations." Shouto raises a brow.

"Like what? How does your quirk work?" Katsuki twists in his grip, turning his (vicious, vicious) glare up at Shouto. When he speaks, every word sounds like he's insulting him. Shouto really doesn't mind.

"The sweat glands in my hands," he says, as if he was speaking to a particularly stupid child, "they can make nitroglycerin. I can control it, usually, but if I'm sweating for real because it's hot or I'm nervous or whatever it's – harder."

The room wasn't hot.

"You were nervous?" Shouto asks, tilting his head. Katsuki does pull away then, scowling as he pushes himself out of Shouto's arms with force.

"No."

Shouto lets his head fall backwards, resting on the wall, watching Katsuki search his pockets for something – god knows what. He looks surprisingly well composed for someone who'd violently shoved Shouto against a wall, violently made out with him, and had his throat fucked like a whore within the last 20 minutes.

Compared to Shouto, with his stained shirt and broken belt and his undoubtedly tousled hair (to be fair, though, Katsuki's hair was messy as default), he looked practically pristine. Shouto always did get the brunt of the property damage between them.

"We're even now," he tells him. Katsuki snorts derisively, continuing to dig into his pockets.

"A handjob isn't equal to sucking you off."

"That's not what I meant, but duly noted."

He stills his movement then, glancing sharply up at him. "What the fuck are you on about."

"Personal information. We've both exchanged." Shouto shifts under Katsuki's gaze.

"Is that what this is about," he mutters, sounding – Shouto's not sure what that tone conveys, but he doesn't look too angry. He finally fishes out what he's been looking for; a small, bent up pack of cigarettes.

"I need a fucking smoke," he says, as if it needed explanation, and heads towards the back door where Shouto and Izuku had carried the tanks in through earlier, out to the alley beyond. Shouto watches his back, expecting the door to shut again, but Katsuki holds the door open and turns his profile to him. Cool air blows inside.

"Coming, Icy?"

Shouto follows, of course.

The air outside is chillier than Katsuki generally prefers, especially in a tank top, but he's got a killer headache and really needs to calm the fuck down before going back to finish his job – his job that he's been distressingly distracted from.

He's in a better mood now, at least.

He leans against the wall, shivering slightly, and pulls out a cigarette from the packet, lighting it up with a small explosion – a spark, really – from the tips of his fingers. Shouto watches him with an impassive expression, contrasting oddly with his otherwise wrecked appearance. Katsuki likes seeing him wrecked.

"Oi, space heater," he says, placing the cig in his mouth, "why don't you make yourself fucking useful for a change, it's cold as shit."

It takes him a second to catch on, then realisation dawns and his mouth quirks almost imperceptably. "I like the cold," he tells Katsuki, but the air around them heats up anyway, and Katsuki hums low in his throat. "Why not just put the coat on?"

He stares at him. "I'm not going to smoke in a fucking lab coat, Shouto."

Shouto rolls his (pretty, pretty) eyes. Katsuki wants to jam his fingers in their sockets. He blows smoke at Shouto's face instead, hoping to make him cough. He doesn't.

"So, tell me again," Katsuki says, loud, "what the fuck's been going on in your tiny head."

Shouto regards him warily.

"I don't think we're in any position to freely exchange personal details about ourselves."

"Who gives a shit? I can take anyone on, doesn't matter if they know my fucking bloodtype or whatever the fuck," he scoffs, taking another drag of his cigarette. "Hell, Deku's known me since we were babies. What's he gonna do, call the fucking cops on me?"

The air gets just a little bit cooler. Shouto stands in silence, studying him inscrutably.

"You know how stupid it is for people like us to get attached," he finally mutters.

Of course Katsuki does. He's never been worried about the possibility, and its hilarious to him that Shouto thinks it could be a problem. He's almost charmed. He would be, were he not losing IQ by even considering the idea.

"Who the fuck's getting attached?" he says, blowing more smoke at Shouto's face. It earns him a glare, this time. "I just like your dick."

Shouto slowly nods.

"Right."

"I don't give a shit if your mom beat you every day," Katsuki continues.

"That was a – it was the one time. My _mother_ was fine otherwise," Shouto says, and grimaces. _Right, daddy issues._ Katsuki grins at him lazily.

"Yeah, see, I don't care, so you can tell me whatever the fuck you want," he says, because he really doesn't, and Shouto's expression inexplicably softens.

"I don't care about you either," Shouto tells him, quietly.

"Good."

"You can tell me, too," he says.

"Fine."

Shouto raises his hand between them, the warm one (warm, not hot), almost touching Katsuki's face, then stops. Katsuki stares at it, and Shouto stares too, and then it falls back as if he wasn't sure what he wanted to do in the first place. Katsuki spits the cigarette out of his mouth, and crushes it under his heavy boot.

"Come on," he says, suddenly feeling restless. He makes towards the door back into the warehouse. "We're not done with these bitches."

Shouto makes a quiet sound, like an exhale, but shorter. Katsuki realises its his approximation of a laugh.

"And you're going to stop avoiding the fucking missions, yeah? I'm tired of having to drag Deku's useless ass with me."

"I'll think about it," Shouto says.

"I swear to fuck I'll take Dabi with me if you don't," Katsuki threathens, opening the door. "And I'll suck _his_ dick." Shouto makes a face.

"Ew. Don't. I'll come."

and here's the chapter uncensored, lol. thanks for readin!


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